Fluid streams often carry particulate material. In some operating environments, it is desirable to remove some or all of the particulate material from the fluid stream. For example, air intake streams to the passenger cabins of vehicles often include particulate material that is undesirable to one or more of the passengers of the vehicles. It is desirable to remove the particulate matter to enhance the comfort of the passengers and/or for aesthetics. Cabin air filters are being incorporated in vehicles more frequently.